1. Field of the Invention
The present invention relates in general to the field of information handling system integrated displays, and more particularly to a system and method for information handling system display backlight protection and monitoring.
2. Description of the Related Art
As the value and use of information continues to increase, individuals and businesses seek additional ways to process and store information. One option available to users is information handling systems. An information handling system generally processes, compiles, stores, and/or communicates information or data for business, personal, or other purposes thereby allowing users to take advantage of the value of the information. Because technology and information handling needs and requirements vary between different users or applications, information handling systems may also vary regarding what information is handled, how the information is handled, how much information is processed, stored, or communicated, and how quickly and efficiently the information may be processed, stored, or communicated. The variations in information handling systems allow for information handling systems to be general or configured for a specific user or specific use such as financial transaction processing, airline reservations, enterprise data storage, or global communications. In addition, information handling systems may include a variety of hardware and software components that may be configured to process, store, and communicate information and may include one or more computer systems, data storage systems, and networking systems.
As enterprises and individuals have grown more reliant on information handling systems, portable information handling systems have become more and more common. Portable information handling systems include an integrated display, such as a liquid crystal display (LCD), an integrated power source, such as a battery, and integrated I/O devices, such as a keyboard so that the systems operate free from hard connections, such as power outlets or external peripherals. Portable information handling systems having wireless capabilities allow end users to communicate from virtually any location that is within reach of a wireless local area network, such as Wi-Fi hotspots, or a wireless wide area network, such as a cellular phone network. Two considerations that end users tend to take into account when purchasing a portable information handling system are the size of the system and the time that the system will operate on battery power before needing to recharge. Smaller portable information handling systems typically weigh less than larger systems and are thus easier to carry and use on the go, however, smaller systems tend to have less room to hold processing components and thus tend to have less processing capability. Although larger systems generally have more room for more capable processing components, components that are more capable tend to use more power, which leads to less operating time on a given battery charge.
One example of a portable information handling system component that impacts size and power consumption of a system is the backlight used to provide illumination behind an LCD panel. Traditionally, cold cathode fluorescent lamps (CCFL) have provided backlight for LCD panels. CCFLs are powered with relatively high voltage alternating currents of up to 1000V provided from an inverter that converts the typical 12V direct current of the system power source. CCFLs are relatively inexpensive and proven components although CCFL inverters are somewhat complex and often include a microcontroller to manage the generation of alternating currents. In contrast to CCFLs, light emitting diode (LED) backlights are a relatively new alternative that illuminate an LCD panel with direct current voltage of approximately 40V provided from a boost regulator. LED backlights provide an energy efficient light source with a reduced footprint for use in smaller portable information handling systems. The boost regulator used to power an LED backlight is typically simpler than the inverter used to power a CCFL backlight. Indeed, a boost regulator is typically a simple analog circuit. The boost regulator and inverter generally lack intelligence to detect and report faults associated with the backlight, however, inverters typically have inherent safety features not found in boost regulators. Since the boost regulator usually operates from the main system power bus, a component failure can bring down the main power rail and cause a system shutdown, even potentially latching the external power adapter if it is plugged in. One option to detect such a fault is to have a fuse blow if an over current occurs, but a blown fuse disables the system and does not provide feedback of the fault. Another option is to integrate a switch in the boost regulator that turns off if current exceeds a preset value, but such a switch is costly and increases power use.